﻿// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Unlit/FrostedGlass"
{
	Properties
	{
		_Radius("Radius", Range(1, 255)) = 1
	}

		Category
	{
		Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Opaque" }

		SubShader
	{
		GrabPass
	{
		Tags{ "LightMode" = "Always" }
	}

		Pass
	{
		Tags{ "LightMode" = "Always" }

		CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"

		struct appdata_t
	{
		float4 vertex : POSITION;
		float2 texcoord: TEXCOORD0;
	};

	struct v2f
	{
		float4 vertex : POSITION;
		float4 uvgrab : TEXCOORD0;
	};

	v2f vert(appdata_t v)
	{
		v2f o;
		o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
		float scale = -1.0;
#else
		float scale = 1.0;
#endif
		o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
		o.uvgrab.zw = o.vertex.zw;
		return o;
	}

	sampler2D _GrabTexture;
	float4 _GrabTexture_TexelSize;
	float _Radius;

	half4 frag(v2f i) : COLOR
	{
		half4 sum = half4(0,0,0,0);

#define GRABXYPIXEL(kernelx, kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely, i.uvgrab.z, i.uvgrab.w)))

		sum += GRABXYPIXEL(0.0, 0.0);
		int measurments = 1;

		for (float range = 0.1f; range <= _Radius; range += 0.1f)
		{
			sum += GRABXYPIXEL(range, range);
			sum += GRABXYPIXEL(range, -range);
			sum += GRABXYPIXEL(-range, range);
			sum += GRABXYPIXEL(-range, -range);
			measurments += 4;
		}

		return sum / measurments;
	}
		ENDCG
	}
		GrabPass
	{
		Tags{ "LightMode" = "Always" }
	}

		Pass
	{
		Tags{ "LightMode" = "Always" }

		CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"

		struct appdata_t
	{
		float4 vertex : POSITION;
		float2 texcoord: TEXCOORD0;
	};

	struct v2f
	{
		float4 vertex : POSITION;
		float4 uvgrab : TEXCOORD0;
	};

	v2f vert(appdata_t v)
	{
		v2f o;
		o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
		float scale = -1.0;
#else
		float scale = 1.0;
#endif
		o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
		o.uvgrab.zw = o.vertex.zw;
		return o;
	}

	sampler2D _GrabTexture;
	float4 _GrabTexture_TexelSize;
	float _Radius;

	half4 frag(v2f i) : COLOR
	{

		half4 sum = half4(0,0,0,0);
		float radius = 1.41421356237 * _Radius;

#define GRABXYPIXEL(kernelx, kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely, i.uvgrab.z, i.uvgrab.w)))

		sum += GRABXYPIXEL(0.0, 0.0);
		int measurments = 1;

		for (float range = 1.41421356237f; range <= radius * 1.41; range += 1.41421356237f)
		{
			sum += GRABXYPIXEL(range, 0);
			sum += GRABXYPIXEL(-range, 0);
			sum += GRABXYPIXEL(0, range);
			sum += GRABXYPIXEL(0, -range);
			measurments += 4;
		}

		return sum / measurments;
	}
		ENDCG
	}
	}
	}
}